In general, refrigerators are apparatuses for keeping foods frozen or at a temperature slightly above freezing temperature by discharging cold air generated by a refrigeration cycle consisting of, for example, a compressor, a condenser, an expansion valve, and an evaporator to lower the temperature in a storage compartment thereof.
A typical refrigerator includes a freezing compartment, in which foods or beverages are kept frozen and a refrigerating compartment, in which foods or beverages are kept cold.
There are several kinds of refrigerators, including a top-mounting type refrigerator, in which a freezing compartment is located above a refrigerating compartment, a bottom-freezer type refrigerator, in which a freezing compartment is located below a refrigerating compartment, and a side-by-side type refrigerator, in which a freezing compartment and a refrigerating compartment are respectively located on left and right sides. The freezing compartment and the refrigerating compartment may be provided with respective doors, and may be accessed through the respective doors.
In addition to such refrigerators, which include a refrigerating compartment and a freezing compartment which are compartmentalized from each other, there is also a refrigerator which allows access to both the refrigerating compartment and the freezing compartment through a single door. This kind of refrigerator is mostly small-sized, and is typically constructed such that the freezing compartment is provided in a predetermined space within the refrigerating compartment.
Among the top-mounting refrigerators, there is also provided a French type refrigerator in which an upper refrigerating compartment is opened and closed by right and left doors. The freezing compartment of the French type refrigerator may also be opened and closed by right and left doors.
Recently, in addition to the original function of keeping foods refrigerated or frozen, the variety of functions provided by refrigerators is increasing. For example, a dispenser is installed to a door of the refrigerator to provide purified water and ice, and a display is installed on the front surface of the door to show the state of the refrigerator and to assist a user in controlling the refrigerator.
The door of a refrigerator is generally constructed to be opaque and to open and close the storage compartment of the refrigerator body. In other words, the door also serves as a thermal insulating wall that defines a refrigerating compartment or a freezing compartment. The difference resides in the fact that the door is a kind of thermal insulating wall that is capable of being opened and closed so as to allow a user to access to the refrigerating compartment or the freezing compartment. Accordingly, it is typical for a user not to know the type, location, etc. of objects stored in the storage compartment before opening the door.
A large amount of cold air is lost when the door of a refrigerator is opened. Accordingly, the loss of cold air accumulates as the door remains in the opened state.
Generally, objects having various shapes are stored in the refrigerating compartment of the freezing compartment. Accordingly, it typically takes a user a rather long time to find and take out a desired object. Specifically, a considerable time is required for the user to look all around the storage compartment and find a desired object in the state in which the door is opened.
That is, the inherent characteristics of the refrigerator inconvenience the user and lead to increased energy consumption.
In recent years, a refrigerator in which only part of a storage compartment is opened has been proposed. For example, a refrigerator which is provided with a sub door for opening and closing a sub storage compartment defined in a main door has been proposed. The sub storage compartment is a portion of the space of the main storage compartment, and is isolated from the main storage compartment by a partition wall. This kind of refrigerator may be referred to as a door-in-door (DID) refrigerator. This DID refrigerator is advantageous in that the outward leakage of cold air from the main storage compartment is considerably reduced when only the sub door is opened.
For example, stored objects, such as beverages, which are frequently taken out of and put back into the storage compartment, are stored in the sub storage compartment, and thus the sub storage compartment can be accessed by opening the sub door while maintaining the main door in the closed state.
There is also a home-bar refrigerator which is equipped with a home-bar door. The home-bar may be considered a very small sized sub storage compartment. Specifically, a small amount of beverages or the like may be stored in the home-bar, which is provided in the rear of the main door through a home-bar door mounted in a very small area of the main door.
A refrigerator in which the home-bar is further enlarged, compared to the home-bar refrigerator, may be referred to as the DID refrigerator.
However, the home-bar refrigerator and the DID refrigerator both have the same problem in that the volume of the sub storage compartment and the amount of objects stored in the sub storage compartment are increased. In other words, it takes a considerable time to open the sub door or the home-bar door and find an object to be taken out, which is inconvenient for the user and increases energy consumption.